Counterflow free pump system



Oct. 23, 1962 c, J, COBERLY ETAL 3,059,581

COUNTERFLOW FREE PUMP SYSTEM 4 Sheets-Sheet 2 Filed NOV. 14, 1960IMVEMYORS.

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59918, ,Kmsvl, Russs44 @KE-RM Unite States Patent Ofiflce 3,059,581Patented Oct. 23, 1962 3,059,581 COUNTERFLOW FREE PUlVIP SYSTEM ClarenceJ. Coberiy, San Marino, and Val Kogut, Compton, Calif., assignors toKobe, Inc., Huntington Park, Califi, a corporation of California FiledNov. 14, 1960, Ser. No. 68,947 14 Claims. (Cl. 103-46) The presentinvention relates in general to fluid operated free pump systems for oilwells and, more particularly, to a free pump system which utilizes thecounterflow or reversed flow principle of Patents Nos. 2,851,954 and2,869,470, respectively granted September 16, 1958 and January 20, 1959to Clarence J. Coberly, one of the inventors of the present free pumpsystem, the latter being an improvement on those disclosed in thepatents mentioned.

Any fluid operated free pump system includes at least two tubings one ofwhich is of a size to permit sliding movement of a free pump unittherethrough between the surface and an operating position in the well.The limited space normally available in the well requires that theremaining tubing or tubings of the system be relatively small, at leastin a parallel tubing system wherein the tubings are located side byside.

In a conventional or standard free pump system of the foregoing nature,the relatively large tubing through which the free pump unit iscirculated between the surface and its operating position in the well isalso utilized to supply operating fluid under pressure to a fluidoperated pump incorporated in the free pump unit. Consequently, theproduction fluid and the spent operating fluid discharged by the pumpmust be conveyed to the surface in a tubing or tubings which are smallerthan the pump tubing. In an open system, to which the present inventionis particularly applicable, the production fluid and the spent operatingfluid are mixed and conveyed to the surface by a single relatively smalltubing.

As discussed in detail in the aforementioned patents, the foregoingconventional or standard free pump system is subject to undesirably highfriction losses and reduced eiflciencies, particularly with highviscosity oils and/or high pump-to-engine area ratios, arising out ofthe use of a relatively small tubing for conveying the production fluidand the spent operating fluid to the surface.

As also discussed in detail in the aforementioned patents, a free pumpsystem utilizing the counterflow or reversed flow principle avoids theforegoing disadvantages of the conventional or standard free pump systemby conveying the production fluid and the spent operating fluid to thesurface through the relatively large pump tubing, instead of through arelatively small tubing, the latter being utilized under suchcircumstances as a supply tubing for conveying operating fluid underpressure downwardly in the well to the pump. This produces noundesirably high friction losses in either the relatively largeproduction tubing, or the relatively small supply tubing, because eachhas adequate capacity to handle the necessary flow therethrough.

In any free pump system, it is necessary, in circulating the pump out ofthe well, to introduce fluid under pressure into the pump tubing belowthe pump by way of a second tubing externally of the pump tubing. With aconventional or standard free pump system, wherein the pump tubing isthe supply tubing and the second tubing is the production tubing, thisposes no problem since it is merely necessary to circulate fluid underpressure downwardly through the production tubing to propel the pumpupwardly through the supply tubing to the surface. Consequently, anordinary or standard free pump can be used, suitable standard free pumpsbeing disclosed in Patents Nos. 2,230,830 and 2,338,903, respectivelygranted on February 4, 1941 and January 11, 1944 to Clarence J. Coberly.

However, with a counterflow free pump system, wherein the pump tubing isthe production tubing and the second tubing is the supply tubing, astandard free pump cannot be used because such a free pump would becirculated out of the well through the production tubing by theoperating fluid introduced through the supply tubing to operate it.Consequently, it is necessary to provide a free pump unit, preferablyincorporating such a standard free pump, having means for preventingcirculation out of the Well by way of the production tubing untilremoval is desired.

The aforementioned Patent No. 2,869,470 discloses a free pump unithaving means for latching the unit in its operating position in the wellagainst a constant upward force applied to the unit by the operatingfluid pressure in the supply tubing, until such time as removal isdesired. This latching means is released by increasing the pressure inthe production tubing until it is higher than the pressure in the supplytubing to a predetermined extent.

The aforementioned Patent No. 2,851,954 discloses a free pump unitincluding normally closed valve means which, when opened, establishesfluid communication between the supply tubing and a downwardly-facingarea of the pump unit to displace the pump unit upwardly through theproduction tubing. This valve means is opened by applying to theproduction tubing a pressure higher than that in the supply tubing by apredetermined amount.

With the foregoing as background, a primary object of the presentinvention is to provide a counterflow free pump system wherein the freepump unit has a downwardly-facing area which is adapted to have thepressure of the operating fluid in the supply tubing applied thereto tocirculate the pump unit out of the well, but which is exposed to theflow of production fluid by the pump during normal operation of the pumpso that the pressure of the operating fluid in the supply tubing cannotact thereon under such conditions.

Another object of the invention is to provide the free pump unit withproduction fluid bypass passage means for bypassing the flow ofproduction fluid discharged by the pump upwardly past thedownwardly-facing area mentioned during normal operation of the pump sothat the flow of production fluid discharged by the pump will not unseatthe free pump unit.

A further object is to provide the free pump unit with means responsiveto a pres-sure in the production tubing higher than that in the supplytubing by a predetermined amount for closing the bypass passage meansand for placing the downwardly-facing area of the pump unit in fluidcommunication with the supply tubing.

Still another object is to provide the free pump unit with an operatingfluid supply passage means for conveying operating fluid from the supplytubing to the downwardly-facing area, and with valve means responsive toa pressure in the production tubing higher than that in the supplytubing by a predetermined amount for closing the bypass passage meansand opening the supply passage means, whereupon the free pump unit maybe circulated out of the well through the production tubing by restoringthe pressure in the supply tubing to a value higher than that in theproduction tubing.

Yet another object of the invention is to provide a free pump unitwherein the aforementioned valve means includes a normally open bypassvalve movable to a closed position to close the bypass passage means,means for biasing the bypass valve toward its closed position,

.3 means for latching the bypass valve in its open position, a normallyclosed supply valve movable to an open position to open the supplypassage means, means retaining the supply valve in its closed position,means responsive to a pressure in the production tubing higher than thatin the supply tubing by a predetermined amount for unlatching the bypassvalve and for moving the supply valve to its open position in oppositionto the action of the retaining means, and means for latching the supplyvalve in its open position.

Another object of the invention is to provide a free pump unit whereinthe aforementioned retaining means is either a spring or a shear pin.

An important object of the invention is to provide a free pump unit ofthe foregoing nature wherein the downwardly-facing area, the productionfluid bypass passage means, the operating fluid supply passage means andthe valve means for opening the supply passage means and closing thebypass passage means are all carried by and/or located within a packermandrel connected to the upper end of a standard fluid operated freepump and carrying downwardly-facing packer cups engageable with theproduction tubing, one of such packer cups forming the downwardly-facingarea mentioned.

An important feature of the present invention is that, with theforegoing construction, a standard fluid operated free pump may be usedin a counterflow free pump system merely by substituting a packermandrel constructed in accordance with the invention for a standardpacker mandrel, no modification of the standard fluid operated tree pumpitself being required.

The foregoing objects, advantages, features and results of the presentinvention, together with various other objects, advantages, features andresults thereof which will be evident to those killed in the free pumpart, may be achieved with the exemplary embodiments of the inventiondescribed in detail hereinafter and illustrated in the accompanyingdrawings, in which:

FIG. 1 is a vertical sectional view on a reduced scale illustrating afluid operated free pump system of the invention as installed in awell;

FIG. 2 is an enlarged horizontal sectional view taken along the arrowedline 2--2 of FIG. 1;

FIG. 3 is a vertical sectional view taken along the arrowed line 3-3 ofFIG. 2;

FIGS. 4 and 5 are downward continuations of FIGS. 3 and 4, respectively;

FIG. 6 is a vertical sectional view taken along the arrowed line 6-6 ofFIG. 2;

FIGS. 7 and 8 are enlarged vertical sectional views taken along thearrowed line 7-7 of FIG. 3 and illustrating various components of theinvention in different operating positions;

FIG. 9 is a horizontal sectional view taken along the arrowed line 99 ofFIG. 7;

FIGS. 10 and 11 are vertical sectional views respectively correspondingto FIGS. 7 and 8, but illustrating another embodiment of the invention;and

FIG. 12 is a horizontal sectional view taken along the arrowed line 1212of FIG. 10.

Referring particularly to FIG. 1 of the drawings, the numeral 13designates a well casing which is set in a well and which is providedwith perforations, not shown, to admit into the casing, fluids fromsurrounding, productive formation. The casing 13 is equipped with acasing head 14 which supports parallel production and supply tubings 16and 18 in the casing, these tubings extending downwardly below the wellfluid level in the casing. The production and supply tubings 16 and 18communicate at their upper ends with a four-way valve 28 operated by ahandle 22, this valve selectively connecting the production tubing andthe supply tubing with an operating fluid supply line 24 and aproduction fluid disposal line 26. Thus, by means of the valve '28,either the production tubing 16, or the supply tubing 18, may bepressurized with operating fluid from the supply line 24.

In accordance with the invention, the production tubing 16 is ofrelatively large diameter to accommodate an elongated, piston-like,fluid operated, free pump unit 28 which may be inserted into the upperend of the production tubing by removing a closure 30 which may containthe usual free pump catcher. The pump unit 28 is circulated downwardlythrough the production tubing 16 by connecting the upper end of theproduction tubing to the supply line 24 until the pump unit arrives atits operating position in a bottom hole housing which is designatedgenerally by the numeral 32. The housing 32 is connected to the lowerend of the production tubing 16 and is also connected to the supplytubing 18, all as will be discussed in more detail hereinafter.

The pump unit 28 includes a fluid operated pump 34 which may, forexample, be similar to those disclosed in the aforementioned PatentsNos. 2,230,830 and 2,338,- 903. Alternatively, the pump 34 may be of thetype disclosed in Patent No. 2,311,157, granted February 16, 1943 toClarence J. Coberly. Consequently, a detailed description of the pump 34herein is unnecessary.

Briefly, when the free pump unit 28 is in its operating position in thehousing 32, the lower end of the pump 34 is seated on a standing valveassembly 36, FIG. 5, located within the housing 32 at the lower endthereof and in fluid communication with the well so that productionfluid from the well may enter the pump 34 by way of the standing valveassembly. The production fluid discharged by the pump 34, and the spentoperating fluid discharged thereby, enter an annulus 38, FIGS. 4 and 5,between the pump and the housing 32, the upper end of this annulus beingclosed by an annular seal 40, FIG. 4, carried by the pump unit 28 andengageable with the housing. The mixture of production fluid and spentoperating fluid flows downwardly through the annulus 38 and through aport 42, FIG. 5, in the housing 32 at the lower end of the annulus, intothe lower end of a bypass pipe 44-. The mixture of production fluid andspent operating fluid flowing upwardly in the bypass pipe 44 leaves theupper end of this pipe through ports 46, FIG. 4, therein whichcommunicate with a port 48 for conveying the mixture in question intothe interior of the housing 32 and thence into the lower end of theproduction tubing 16. The production fluid and spent operating fluidmixture flows upwardly through the production tubing 16 in a manner tobe described hereinafter.

As shown in FIG. 6 of the drawings, the supply tubing 18 communicates atits lower end with a passage 50 in the housing 32. The housing isprovided therein at the lower end of the passage 50 with ports 52connecting the passage 50 to an annulus 54 around the pump unit 28. Theoperating fluid under pressure entering the annulus 54 from the supplytubing 18 is separated from the production fluid and spent operatingfluid mixture in the aunulus 38 by the annular seal 40, and is separatedfrom the mixture in question in the production tubing 16 by anotherannular seal 56 carried by the pump unit 28 and engaging the housing 32.The pump unit 28 is provided with an operating fluid inlet 58 whichadmits operating fluid under pressure from the annulus 54 into anoperating fluid supply passage means 59, FIG. 4, in the pump unit. Thelower end of the supply passage means 59 communicates with the pump 34to deliver thereto operating fluid under pressure for operating the pumpin the usual manner.

The operating fluid inlet 58 is formed in, and the annular seals 40 and56 are carried by, and adapter 62 the lower end of which is connected tothe upper end of the pump 34. Connected to the upper end of the adapter62 is a packer mandrel 64, FIGS. 3, 4 and 6, which extends upwardly intothe production tubing 16 a relatively short distance, the correspondingportion of the production tubing being regarded herein as forming a partof the bottom hole housing 32. The packer mandrel 64 carriesdownwardly-facing packer cups 66 and 68, FIG. 3, which engage theproduction tubing 16. As is well known in the art, the packer cups 66and 68 make fluid-tight seals with the production tubing 16 whensubjected to pressures therebeneath higher than the pressures thereabovein circulating the free pump unit 28 upwardly through the productiontubing 16 to the surface. On the other hand, the packer cups 66 and 68will permit fluid to flow downwardly therepast when the pressuresthereabove are higher than the pressures therebeneath. The packermandrel 64 terminates at its upper end in the usual packer nose cap 69having thereon a tapered head 70 which is engageable by theaforementioned pump catcher on the closure 30 when the free pump unit 28reaches the surface.

The packer mandrel 64 is provided therein with an axial production fluidbypass passage means 72 provided with an inlet 74 below the lower packercup 66 and an outlet 76 in the packer nose cap 69 above the upper packercup 68. As will be described in more detail hereinafter, the bypasspassage means 72 is normally open so that the production fluid and spentoperating fluid mixture discharged by the pump 34 may bypass the packercups 66 and 68 and flow upwardly therepast into the production tubing 16above the packer cups. Consequently, there is no tendency for theproduction fluid and spent operating fluid mixture to act on thedownwardly-facing areas of the packer cups 66 and 68 to tend to unseatthe free pump unit 28. The packer mandrel 64 carries a standing valve78, FIG. 3, which prevents downward flow of fluid through the bypasspassage means 72.

An Operating fluid supply passage means 60 extends upwardly from theoperating fluid inlet 58 through the adapter 62 and into the lower endof the packer mandrel 64. The supply passage means 60 terminates at itsupper end in an operating fluid outlet 88 communicating with theproduction tubing 16 below the inlet 74 of the bypass passage means 72.The supply passage means 60 is normally closed, i.e., is closed when thepump 34 is in operation. However, when it is desired to circulate thefree pump unit 28 out of the well, the bypass passage means 72 is closedand the supply passage means 68 is opened, as will be describedhereinafter. Consequently, operating liquid under pressure from thesupply tubing 18 may be delivered to the production tubing 16 below thelower packer cup 66 to act upwardly on such packer cup so as tocirculate the free pump unit 28 upwardly through the production tubing16 and out of the Well.

Turning now to FIGS. 7 to 9 of the drawings, the packer mandrel 64contains valve means 82, responsive to a fluid pressure in theproduction tubing 16 higher by a predetermined amount than that in thesupply tubing 18, for closing the normally open bypass passage means 72and for opening the normally closed supply passage means 60.Consequently, when the pressure in the supply tubing 18 is subsequentlyincreased to a value higher than that in the production tubing 16,operating fluid under pressure from the supply tubing 18 may flowthrough the supply passage means 60 and out the operating fluid outlet80 into the production tubing 16 below the lower packer cup 66 so as toact on the downwardly-facing area at the lower end of such packer cup tocirculate the free pump unit 28 upwardly through the production tubing16 to the surface.

Considering the valve means 82 in a general way, it includes a bypassvalve 84 which normally occupies an open position, as shown in FIG. 7,but which is movable into a closed position, FIG. 8, wherein it engagesa valve seat 86 in the bypass passage means 72 to prevent upward flowthrough the bypass passage means from the annular space around thepacker mandrel 64 below the lower packer cup 66. The valve means 82 alsoincludes a supply valve 88 which normally occupies a closed position, asshown in FIG. 7, wherein it engages a valve seat 90 in the supplypassage means 60, but which is movable to an open position, as shown inFIG. 8, to permit upward flow of operating fluid under pressure from thesupply tubing 18 into the annular clearance below the lower packer cup66 by way of the operating fluid outlet in the packer mandrel.

In the construction illustrated, the bypass valve 84 has the form of aninverted cup which is telescoped over an inner guide 92, the upper endof the bypass valve being slidable in an axial bore 94 in the packermandrel 64 and the lower end of the bypass valve being slida-ble on theguide 92. A compression spring 96 within the bypass valve 84 and seatedon the upper end of the guide 92 biases the bypass valve toward itsclosed position.

The guide 92 also has the form of an inverted cup and is provided at itslower end with an annular flange 98 clamped between an annular shoulderon the packer mandrel 64 and a member 100 through which the supplypassage means 68 extends and which provides the valve seat 98 for thesupply valve 88. The guide 92 is held against rotation relative to themember 100 by a pin 102.

The supply valve 88 is disposed within the guide 92 and is biaseddownwardly into engagement with the valve seat by a compression spring104 disposed within the guide and seated against the upper end of thesupply valve. An axial passage 106 through the supply valve 88 appliesthe operating fluid pressure in the supply passage means 60 to the upperend of the supply valve when the latter is in its closed position,whereby the operating fluid pressure assists the spring. 104 inmaintaining the supply valve seated since the operating fluid pressureacts on an area at the lower end of the supply valve which is less thanthe area of the upper end thereof.

The upper portion of the supply valve 88 has a larger diameter than thelower portion thereof and is slidable in a major bore 108 in the guide92. The smaller lower portion of the supply valve 88 is slidable in aminor bore 110 in a portion of the member which extends upwardly intothe guide 92. This portion of the member 108 and the guide 92 areprovided therethrough with registering ports 112 and 114 which arecovered by the lower end of the bypass valve 84 when it is in its openposition, but which are uncovered and communicate with the operatingfluid outlet 80 in the packer mandrel 64 when the bypass valve 84 is inits closed positon, as shown in FIG. 8.

During operation of the pump 34, the bypass valve 84 is latched in itsopen position by a latch means 116 actuated by the supply valve 88.Movement of the supply valve 88 to its open position results inreleasing the latch means 116 so that the bypass valve 84 may be movedto its closed position by the spring 96. When the bypass valve 84 is inits closed position, it, in turn, causes the latch means 116 to hold thesupply valve 88 in its open position in opposition to the action of thespring 104.

Considering the latch means 116 in more detail, it includescircumferentially spaced ball detents 118 disposed in radial openings inthe guide 92 intermediate the major bore 108 in the guide and the minorbore in the member 100. When the supply valve 88 is in its closedposition and the bypass valve 84 is in its open position, the majordiameter of the supply valve displaces the ball detents 118 outwardly,as shown in FIG. 7, into an internal annular groove 120 in the bypassvalve 84, thereby latching the bypass valve in its open position. Uponmovement of the supply valve 88 into its open position, as shown in FIG.8, the ball detents 118 may move radially inwardly into an externalannular groove 122 in the supply valve intermediate its major and minordiameters. Under such conditions, the spring 96 displaces the bypassvalve 84 upwardly into its closed position, at the same time moving theinternal annular groove 120 in the bypass valve upwardly out 6 ofregister with the ball detents 118. Under such conditions, the balldetents 118 latch the supply valve 88 in its open position.

Considering the manner in which the supply valve 88 is moved upwardlyinto its open position to release the bypass valve 84, this isaccomplished by applying to a downwardly-facing annular area 124 of thesupply valve 88, which area is equal to the difference between the areasof the major bore 108 and the minor bore 110, a fluid pressure which issufliciently higher than the fluid pressure in the supply passage means68 to overcome the spring 104. As will be explained, the higher pressureapplied to the area 124 is developed by increasing the pressure in theproduction tubing 16 above that which exists during pumping and bydecreasing the pressure in the supply tubing 18 to a value below that inthe production tubing 16. This higher pressure in the production tubing16 reaches the area 124 by way of the operating fluid outlet 80 in thepacker mandrel 64, an annular clearance 126 between the packer mandreland the bypass valve 84, ports 128 through the bypass valve, theinternal annular groove 128 in the bypass valve, and the radial openingsin the guide 92 in which the ball detents 118 are disposed. The ports128 in the bypass valve 84, and ports 130 therein, also interconnect theannular clearance 126 with an annular clearance 132 between the bypassvalve and the guide 92 so that the pressure existing in the productiontubing 16 is communicated to the interior of the cup-shaped bypass valve84. The bypass valve is therefore hydraulically balanced when it is inits open position, and is hydraulically held in its closed positionduring circulation of the free pump unit 28 out of the well.

Operation Prior to running the free pump unit 28 into its operatingposition in the housing 32, the bypass and supply valves 84 and 88 must,of course, be in their open and closed positions, respectively, as shownin FIG. 7. If they are initially in their closed and open positions,respectively, as shown in FIG. 8, they may be re-set by unscrewing thepacker nose cap 69, dropping a long bar, not shown, into the packermandrel, and pushing downwardly thereon to return the bypass valve 84 toits open position. This results in unlatching of the supply valve 88 sothat its spring 104 may return it to its closed position, the latchmeans 116 then latching the bypass valve in its open position. Thisaccomplished, the resetting bar is removed and the packer nose cap 69 isreplaced.

Next, the closure 30 for the upper end of the production tubing 16 isremoved, the free pump unit 28 is inserted into the upper end of theproduction tubing, and the closure is replaced. Thereupon, the valve isoperated to connect the upper end of the production tubing 16 to theoperating fluid supply line 24, the valve 20 simultaneously connectingthe supply tubing 18 to the production fluid disposal line 26.Preferably, the valve 20 is provided with some means, not shown, forlimiting the operating fluid pressure which can be applied to theproduction tubing 16 under such conditions to a value less than thepredetermined minimum pressure required to open the supply valve 88while the free pump unit 28 is being run in and seated, thereby insuringagainst any possibility of opening the supply valve 88 and closing thebypass valve 84 inadvertently.

Under the foregoing conditions, the pump unit 28 moves downwardlythrough the production tubing 16 into the housing 32 and seats on thestanding valve assembly 36, fluid in the production tubing 16 beneaththe pump unit being displaced upwardly through the supply tubing 18. Thepump unit 28 is now ready for operation.

To operate the pump 34, the control valve 28 at the surface is set in aposition to place the supply tubing 18 in communication with theoperating fluid supply line a 24- and to place the production tubing 16in communication with the production fluid disposal line 26.Consequently, operating fluid under pressure is delivered to the pumpthrough the supply tubing 18 to operate the pump, the spent operatingfluid and the production fluid discharged by the pump being conveyed tothe surface by way of, among other elements, the bypass pipe 44, theproduction tubing 16 below the packer cups 66 and 68, the bypass passagemeans 72 in the packer mandrel 64-, and the production tubing 16 abovethe free pump unit 28.

"(when it is desired to remove the free pump unit 28 from the well, thecontrol valve 20 at the surface is again operated to place theproduction tubing 16 in communication with the operating fluid supplyline 24 and to place the supply tubing 18 in communication with the prodtion fluid disposal line 26. Under these conditions, sure in theproduction tubing 16 is considerably higher man that in the supplytubing 18, and such higher pressure also exists in the production tubing16 below the packer cups 66 and 68 since such cups will not seal againstthe reversed application of pressure. The relatively low pressure in thesupply tubing 18 is applied to the upper end of the supply valve 88through the supply passage means 68 and the axial passage 106 throughthe supply valve. On the other hand, the relatively high pressure in theproduction tubing 16 is applied to the downwardlyfacing annular area 12-r of the supply valve 88, in the manner hereinbetore described, to openthe supply valve in opposition to the action of the spring 184, thisspring being designed to yield to a predetermined pressure differentialbetween the production tubing and the supply tubing. Opening of thesupply valve 88 results in unlatching of the bypass valve 84, whereuponthe bypass valve is moved to its closed position by the spring 96.Simultaneously, the bypass valve 84 causes the latch means 116 to latchthe supply valve in its open position. Thus, the various components ofthe valve means 82 now occupy the positions shown in FIG. 8 of thedrawings.

The next step is to again set the control valve 20 at the surface in aposition to connect the supply tubing 18 in communication with theoperating fluid supply line 24 and to connect the production tubing 16in communication with the production fluid disposal line 26. Operatingfluid under pressure is now delivered downwardly through the supplytubing 18 to the production tubing 16 below the lower packer cup 66 byway of the supply passage means 66, this being possible because thesupply valve 88 is now in its open position. The operating fluid thusdelivered to the production tubing 16 below the packer cup 66 isconfined beneath this packer cup because of the fact that the bypasspassage means 72 is now closed by the bypass valve 84. Consequently, thefree pump unit 28 is caused to move upwardly through the productiontubing 16 to the surface and is ultimately caught by the aforementionedpump catcher on the closure 30. Upon removal of this closure, the freepump unit 28 may be removed.

Thus, the present invention provides the advantages of using the largepump tubing 16 as the production tubing in a fluid operated free pumpsystem of the open type, without any modification of the fluid operatedpump 34, other than to substitute for the usual packer mandrel thedisclosed packer mandrel 64 incorporating the valve means 82 of theinvention. This is an important feature since it means that any standardfluid operated pump may be utilized, without modification of the pumpitself, to achieve the advantages of a large production tubing.

Another advantage of the present invention is that it permits the packercups 66 and 68 to remain in sealing engagement with the productiontubing 16 at all times, except when downward flow therepast occurs inthe course of pressurizing the production tubing to close the bypassvalve 84 and to open the supply valve 88. In other words, since theproduction fluid and spent operating fluid mixture bypasses the packercups 66 and 68 during normal operation by way of the bypass passagemeans 72, it is unnecessary to locate the packer cups in an enlargedhousing, as disclosed in the aforementioned Patents Nos. 2,851,954 and2,869,470. With the structures of these patents, it is necessary for thefree pump unit to move up several inches before the upper packer cupengages the production tubing to produce a fluid tight seal which wouldlift the pump unit upwardly through the production tubing. Such priorstructures therefore require an auxiliary seal adjacent the bottom ofthe free pump unit against which the fluid pressure utilized to lift thepump unit can act until sealing engagement between the upper packer cupand the production tubing is achieved. With the present invention, sincethe packer cups 66 and 68 are always in sealing engagement with theproduction tubing 16 with respect to a higher fluid pressuretherebeneath, no auxiliary sealing means of the nature mentioned isrequired.

FIGS. to 12 Referring to FIGS. 10 to 12 of the drawings, the packermandrel 64 in this embodiment of the invention incorporates a valvemeans 144 which is similar to and performs the same functions as the-valve means 82. More particularly, the valve means 140 includes thesame bypass valve 84, guide 92 and bypass valve spring 96 as the valvemeans 82, the valve means 140 diflering only in substituting a dilferentsupply valve 142 for the supply valve 88 and a different member 144 forthe member 100.

The supply valve 142, instead of being movable upwardly from its closedposition to its open position as is the case with the supply valve 88,is movable downwardly from its closed position, shown in FIG. 10, to itsopen position, shown in FIG. 11 When the supply valve 142 is in itsclosed position, it is seated on a valve seat 146 provided by the member144, being held against such seat by the operating fluid pressure in thesupply passage means 60 during operation of the pump 34. Thus, no springis necessary. The supply valve 142 is maintained substantially inseating engagement with the valve seat 146 when the pump 34 is not inoperation by a shear pin 148 which extends through the supply valve intothe member 144 and which makes a loose fit in the member 144 so that theshear pin will not interfere with proper seating of the supply valve onthe valve seat 146 under the influence of operating fluid pressure inthe supply passage means 60. When the supply valve 142 is in its openposition, as shown in FIG. 11, it engages a stop pin 150 which limitsdownward movement thereof, this stop pin being carried by the adapter62. With the supply valve 142 in its open position, fluid may flow fromthe supply passage means 60 into the production tubing '16 below thepacker cup 66 by way of an annular clearance between the member 144 anda reduced-diameter portion 152 of the supply valve, by way of the ports114 in the guide 92, and by way of the operating fluid outlet 80 in thepacker mandrel 64.

As long as the supply valve 142 is in its closed position, as shown inFIG. 10, the portion thereof above the reduced-diameter portion 152maintains the ball detents 118 in their radially outward positionswithin the internal annular groove 120 in the bypass valve 84 to latchthe bypass valve in its open position. However, when the supply valve142 is moved downwardly into its open position, as shown in FIG. 11, theball detents 118 move radially inwardly into an external annular groove154 in the supply valve 142. When this occurs, the bypass valve spring96 closes the bypass valve 84, whereupon the bypass valve holds the'ball detents 118 in their radially inward positions to latch the supplyvalve 142 in its open position.

Considering the manner in which the supply valve 142 is moved from itsclosed position to its open position, the first step is to increase thepressure in the production tubing 16 below the packer cup 66 above thepressure in the'supply tubing 18 by a predetermined amount, this beingaccomplished in the manner hereinbefore described. Under theseconditions, (the lower end of the supply valve 142 is exposed to arelatively low pressure in the supply passage means 60, while arelatively high pressure is present in the production tubing 16. Thishigher pressure enters the annulus around the reduced-diameter portion152 of the supply valve 142 by way of the operating fluid outlet 80, theannular clearance 126 between the packer mandrel 64 and the bypass valve84, the ports 128 in the bypass valve, the internal annular groove inthe bypass valve, and the radial openings in the guide 92 in which theball detents 118 are disposed. From the annular clearance around thereduced-diameter portion 152 of the supply valve 142, the relativelyhigh pressure fiuid in the production tubing 16 flows through radialports 156 and an axial passage 158 in the supply valve to the upper endthereof. The pressure in the guide 92 above the supply valve 142ultimately builds up to a valve sufliciently high to shear the pin 148,whereupon the supply valve 142 drops downwardly into its open position.The rate at which the supply valve 142 moves downwardly is determined bythe flow resistance offered by the ports 156 and the passage 158.

When the supply valve 142 reaches its open position, it unlatches thebypass valve 84, which then moves to its closed position to close thebypass passage means 72, and which at the same time causes the latchmeans 116 to latch the supply valve 142 in its open position.

The operation of the invention utilizing the valve means is the same asthe operation of the invention utilizing the valve means 82.Consequently, a further description will not be required.

It should be noted that the pressure utilized to open the supply valve142 acts on the entire area of the upper end thereof to shear the pin148. On the other hand, the pressure for opening the supply valve 88acts only on the relatively small area 124 thereof, the reason being toavoid an excessively heavy spring for the supply valve spring 104.

In order to re-set the valve means 140, the packer mandrel 64 is firstunscrewed from the adapter 62, whereupon the various parts of the valvemeans 140 may be removed. The parts of the sheared pin are then removedand a new pin installed to interconnect the member 144 and the supplyvalve 142. The parts of the valve means 140 are then reassembled, withthe supply valve 142 held substantially in its closed position by theshear pin 148, by compressing the bypass valve spring 96 sufliciently tolatch the bypass valve 84 in its closed position relative to the guide92. The resulting assembly is then inserted into the packer mandrel 64and the packer mandrel is reconnected to the adapter 62. The valve means140 is now ready for re-use.

Although exemplary embodiments of the invention have been disclosedherein for purposes of illustration, it will be understood that variouschanges, modifications and substitutions may be incorporated in suchembodiments without departing from the spirit of the invention asdefined by the claims which follow.

We claim:

1. In a fluid operated free pump system for a well, the combination of:a supply tubing and a production tubing set in the well with said supplytubing externally of said production tubing, said production tubinghaving a housing at the lower end thereof with which said supply tubingcommunicates; a free pump unit, including a fluid operated pump,slidable through said production tubing into said housing, said pumpbeing operable in said housing by operating fluid under pressuresupplied thereto through said supply tubing to pump production fluidfrom the well into said production tubing, said pump unit having adownwardly-facing area exposed to the flow of production fluiddischarged by said pump when said pump is in operation in said housing;production 11 fluid bypass passage means in said pump unit for bypassingthe flow of production fluid discharged by said pump past saiddownwardly-facing area; and means car ried by said pump unit for closingsaid bypass passage means and for placing said downwardly-facing area influid communication with said supply tubing.

2. In a fluid operated free pump system for a well, the combination of:a supply tubing and a production tubing set in the well with said supplytubing externally of said production tubing, said production tubinghaving a housing at the lower end thereof with which said supply tubin-gcommunicates; a free pump unit, including a fluid operated pump,slidable through said production tubing into said housing, said pumpbeing operable in said housing by operating fluid under pressuresupplied thereto through said supply tubing to pump production fluidfrom the well into said production tubing, said pump unit having adownwardly-facing area exposed to the flow of production fluiddischarged by said pump when said pump is in operation in said housing;production fluid bypass passage means in said pump unit for bypassingthe flow of production fluid discharged by said pump past saiddownwardly-facing area; and means carried by said pump unit andresponsive to a pressure in said production tubing higher than that insaid supply tubing for closing said bypass passage means and for placingsaid downwardly-facing area in fluid communication with said supplytubing.

3. In a fluid operated free pump system for a well, the combination of:a supply tubing and a production tubing set in the well with said supplytubing externally of said production tubing, said production tubinghaving a housing at the lower end thereof with which said supply tubingcommunicates; a free pump unit, including a fluid operated pump,slidable through said production tubing into said housing, said pumpbeing operable in said housing by operating fluid under pressuresupplied thereto through said supply tubing to pump production fluidfrom the well into said production tubing, said pump unit having adownwardly-facing area exposed to the flow of production fluiddischarged by said pump when said pump is in operation in said housing;production fluid bypass passage means in said pump unit for bypassingthe flow of production fluid discharged by said pump past saiddownwardly-facing area; operating fluid supply passage means in saidpump unit for conveying operating fluid from said supply tubing to saiddownwardly-facing area; and valve means carried by said pump unit andresponsive to a pressure in said production tubing higher than that insaid supply tubing for closing said bypass passage means and openingsaid supply passage means.

4. In a fluid operated free pump system for a well, the combination of:a supply tubing and a production tubing set in the well with said supplytubing externally of said production tubing, said production tubinghaving a housing at the lower end thereof with which said supply tubingcommunicates; a free pump unit, including a fluid operated pump,slidable through said production tubing into said housing, said pumpbeing operable in said housing by operating fluid under pressuresupplied thereto through said supply tubing to pump production fluidfrom the well into said production tubing, said pump unit having adownwardly-facing area exposed to the flow of production fluiddischarged by said pump when said pump is in operation in said housing;production fluid bypass passage means in said pump unit for bypassingthe flow of production fluid discharged by said pump past saiddownwardly-facing area; operating fluid supply passage means in saidpump unit for conveying operating fluid from said supply tubing to saiddownwardly-facing area; and valve means carried by said pump unit andresponsive to a pressure in said production tubing higher than that insaid supply tubing for closing said bypass passage means and openingsaid supply passage means, said valve means including a normally openbypass valve movable to a closed position to close said bypass passagemeans, means for biasing said bypass valve toward its closed position,means for latching said bypass valve in its open position, a normallyclosed supply valve movable to an open position to open said supplypassage means, means retaining said supply valve in its closed position,and means responsive to a pressure in said production tubing higher thanthat in said supply tubing for unlatching said bypass valve and formoving said supply valve to its open position in opposition to theaction of said retaining means.

5. In a fluid operated free pump system for a well, the combination of:a supply tubing and a production tubing set in the well with said supplytubing externally of said production tubing, said production tubinghaving a housing at the lower end thereof with which said supply tubingcommunicates; a free pump unit, including a fluid operated pump,slidable through said production tubing into said housing, said pumpbeing operable in said housing by operating fluid under pressuresupplied thereto through said supply tubing to pump production fluidfrom the well into said production tubing, said pump unit having adownwardly-facing area exposed to the flow of production fluiddischarged by said pump when said pump is in operation in said housing;production fluid bypass passage means in said pump unit for bypassingthe flow of production fluid discharged by said pump past saiddownwardly-facing area; operating fluid supply passage means in saidpump unit for conveying operating fluid from said supply tubing to saiddownwardliy-facing area; and valve means carried by said pump unit andresponsive to a pressure in said production tubing higher than that insaid supply tubing for closing said bypass passage means and openingsaid supply passage means, said valve means including a normally openbypass valve movable to a closed position to close said bypass passagemeans, means for biasing said bypass valve toward its closed position,means for latching said bypass valve in its open position, a normallyclosed supply valve movable to an open position to open said supplypassage means, means retaining said supply valve in its closed position,and means responsive to a pressure in said production tubing higher thanthat in said supply tubing for unlatching said bypass valve and formoving said supply valve to its open position in opposition to theaction of said retaining means, said retaining means comprising aspring.

6. In a fluid operated free pump system for a well, the combination of:a supply tubing and a production tubing set in the well with said supplytubing externally of said production tubing, said production tubinghaving a housing at the lower end thereof with which said supply tubingcommunicates; a free pump unit, including afluid operated pump, slidablethrough said production tubing into said housing, said pump beingoperable in said housing by operating fluid under pressure suppliedthereto through said supply tubing to pump production fluid from thewell into said production tubing, said pump unit having adownwardly-facing area exposed to the flow of production fluiddischarged by said pump when said pump is in operation in said housing;production fluid bypass passage means in said pump unit for bypassingthe flow of production fluid discharged by said pump past saiddownwardly-facing area; operating fluid supply passage means in saidpump unit for conveying operating fluid from said supply tubing to saiddownwardly-facing area; and valve means carried by said pump unit andresponsive to a pressure in said production tubing higher than that insaid supply tubing for closing said bypass passage means and openingsaid supply passage means, said valve means including a normally openbypass valve movable to a closed position to close said bypass passagemeans, means for biasing said bypass valve toward its closed position,means for latching said bypass valve in its open position, a normallyclosed supply valve movable to an open position to open said supplypassage means, means retaining said supply valve in its closed position,and means responsive to a pressure in said production tubing higher thanthat in said supply tubing for unlatching said bypass valve and formoving said supply valve to its open position in opposition to theaction of said retaining means, said retaining means comprising a shearpin.

7. An elongated, piston-like free well pump unit movable through atubing set in a well between the surface of the ground and an operatingposition in the well, said movable pump unit including a fluid operatedpump operable by an operating fluid under pressure to pump productionfluid from the well through said tubing, said movable pump unit havingan area which faces downwardly when said movable pump unit is in itsoperating position and which is adapted to be exposed to the flow ofproduction fluid discharged by said pump when said pump is in operation,said movable pump unit being provided therein with production fluidbypass passage means for bypassing the flow of production fluiddischarged by said pump past said downwardly-facing area, said movablepump unit being provided therein with an operating fluid supply passagemeans for conveying operating fluid to said downwardly-facing area, saidmovable pump unit being provided therein with valve means for closingsaid bypass passage means and opening said supply passage means, saidbypass passage means, said supply passage means, and said valve meansbeing entirely within the confines of said movable pump unit.

8. A free well pump unit, including: a fluid operated pump having upperand lower ends and having an operating fluid inlet adjacent its upperend, said pump being operable by operating fluid under pressure suppliedthereto through said operating fluid inlet to pump production fluid froma well; a packer mandrel having upper and lower ends and connected atits lower end to the upper end of said pump; at least onedownwardly-facing packer cup on said packer mandrel; production fluidbypass passage means in said packer mandrel and having a productionfluid inlet below said packer cup and a production fluid outlet abovesaid packer cup; operating fluid supply passage means in said packermandrel communicating with said operating fluid inlet in said pump andhaving an operating fluid outlet below said packer cup; and valve meansin said packer mandrel for closing said bypass passage means and openingsaid supply passage means.

9. A free well pump unit, including: a fluid operated pump having upperand lower ends and having an operating fluid inlet adjacent its upperend, said pump being operable by operating fluid under pressure suppliedthereto through said operating fluid inlet to pump production fluid froma well; a packer mandrel having upper and lower ends and connected atits lower end to the upper end of said pump; at least onedownwardly-facing packer cup on said packer mandrel; production fluidbypass passage means in said packer mandrel and having a productionfluid inlet below said packer cup and a production fluid outlet abovesaid packer cup; operating fluid supply passage means in said packermandrel communicating with said operating fluid inlet in said pump andhaving an operating fluid outlet below said packer cup; and valve meansin said packer mandrel for closing said bypass passage means and openingsaid supply passage means, said valve means including a normally openbypass valve movable to a closed position to close said bypass passagemeans, means for biasing said bypass valve toward its closed position,means for latching said bypass valve in its open position, a normallyclosed supply valve movable to an open position to open said supplypassage means, means retaining said supply valve in its closed position,and means for unlatching said bypass valve and for moving said supplyvalve to its open position in opposition to the action of said retainingmeans.

'10. A free well pump unit, includingfa fluid operated pump having upperand lower ends and having an operating fluid inlet adjacent its upperend, said pump being operable by operating fluid under pressure suppliedthereto through said operating fluid inlet to pump production fluid froma well; a packer mandrel having upper and lower ends and connected atits lower end to the upper end of said pump; at least onedownwardly-facing packer cup on said packer mandrel; production fluidbypass passage means in said packer mandrel and having a productionfluid inlet below said packer cup and a production fluid outlet abovesaid packer cup; operating fluid supply passage means in said packermandrel communicating with said operating fluid inlet in said pump andhaving an operating fluid outlet below said packer cup; and valve meansin said packer mandrel for closing said bypass passage means and openingsaid supply passage means, said valve means including a normally openbypass valve movable to a closed position to close said bypass passagemeans, means for biasing said bypass valve toward its closed position,means for latching said bypass valve in its open position, a normallyclosed supply valve movable to an open position to open said supplypassage means, means retaining said supply valve in its closed position,and pressure difiierential responsive means for unlatching said bypassvalve and for moving said supply valve to its open position inopposition to the action of said retaining means.

11. A free well pump unit, including: a fluid operated pump having upperand lower ends and having an operating fluid inlet adjacent its upperend, said pump being operable by operating fluid under pressure suppliedthereto through said operating fluid inlet to pump production fluid froma well; a packer mandrel having upper and lower ends and connected atits lower end to the upper end of said pump; at least onedownwardly-facing packer cup on said packer mandrel; production fluidbypass passage means in said packer mandrel and having a productionfluid inlet below said packer cup and .a production fluid outlet abovesaid packer cup; operating fluid supply passage means in said packermandrel communicating with said operating fluid inlet in said pump andhaving an operating fluid outlet below said packer cup; and valve meansin said packer mandrel for closing said bypass passage means and openingsaid supply passage means, said valve means including a normally openbypass valve movable to a closed position to close said bypass passagemeans, means for biasing said bypass valve toward its closed position,means for latching said bypass valve in its open position, a normallyclosed supply valve movable to an open position to open said supplypassage means, means retaining said supply valve in its closed position,and pressure differential responsive means for unlatching said bypassvalve and for moving said supply valve to its open position inopposition to the action of said retaining means, said retaining meanscomprising a spring.

12. A free well pump unit, including: a fluid operated pump having upperand lower ends and having an operating fluid inlet adjacent its upperend, said pump being operable by operating fluid under pressure suppliedthereto through said operating fluid inlet to pump production fluid froma well; a packer mandrel having upper and lower ends and connected atits lower end to the upper end of said pump; at least onedownwardly-facing packer cup on said packer mandrel; production fluidbypass passage means in said packer mandrel and having a productionfluid inlet below said packer cup and a production fluid outlet abovesaid packer cup; operating fluid supply passage means in said packermandrel communicating with said operating fluid inlet in said pump andhaving an operating fluid outlet below said packer cup; and valve meansin said packer mandrel for closing said bypass passage means and openingsaid supply passage means, said valve means including a normally openbypass valve movable to a closed position to close said bypass passagemeans, means for biasing said bypass valve toward its closed position,means for latching said bypass valve in its open position, a normallyclosed supply valve movable to an open position to open said supplypassage means, means retaining said supply valve in its closed position,and pressure differential responsive means for unlatching said bypassvalve and for moving said supply valve to its open position inopposition to the action of said retaining means, said retaining meanscomprising a shear pin.

13. In a fluid operated free pump system for a well, the combination of:a supply tubing and a production tubing set in the well with said supplytubing externally of said production tubing, said production tubinghaving a housing at the lower end thereof with which said supply tubingcommunicates; a free pump unit, including a fluid operated pump,slidable through said production tubing into said housing, said pumpbeing operable in said housing by operating fluid under pressuresupplied thereto through said supply tubing to pump production fluidfrom the well into said production tubing, said pump unit having adownwardly-facing area exposed to the flow of production fluiddischarged by said pump when said pump is in operation in said housing;production fluid bypass passage means in said pump unit for bypassingthe flow the production fluid discharged by said pump past saiddownwardly-facing area; operating fluid supply passage means in saidpump unit for conveying operating fluid from said supply tubing to saiddownwardly-facing area; and valve means carried by said pump unit andresponsive to a pressure in said production tubing higher than that insaid supply tubing for closing said bypass passage means and openingsaid supply passage means, said valve means including a normally openbypass valve movable to a closed position to close said bypass passagemeans, means for biasing said bypass valve toward its closed position,means for latching said bypass valve in its open position, a normallyclosed supply valve movable to an open position to open said supplypassage means, means retaining said supply valve in its closed position,means responsive to a pressure in said production tubing higher thanthat in 16 said supply tubing for unlatching said bypass valve and formoving said supply valve to its open position in opposition to theaction of said retaining means, and means for latching said supply valvein its open position upon movement of said bypass valve to its closedposition.

14. A free well pump unit, including: a fluid operated pump having upperand lower ends and having an operating fluid inlet adjacent its upperend, said pump being operable by operating fluid under pressure suppliedthereto through said operating fluid inlet to pump production fluid froma well; a packer mandrel having upper and lower ends and connected atits lower end to the upper end of said pump; at least onedownwardly-facing packer cup on said packer mandrel; production fluidbypass passage means in said packer mandrel and having a productionfluid inlet below said packer cup and a production fluid outlet abovesaid packer cup; operating fluid supply passage means in said packermandrel communicating with said operating fluid inlet in said pump andhaving an operating fluid outlet below said packer cup; and valve meansin said packer mandrel for closing said bypass passage means and openingsaid supply passage means, said valve means including a normally openbypass valve movable to a closed position to close said bypass passagemeans, means for biasing said bypass valve toward its closed position,means for latching said bypass valve in its open position, a normallyclosed supply valve movable to an open position to open said supplypassage means, means retaining said supply valve in its closed position,means for unlatching said bypass valve and for moving said supply valveto its open position in opposition to the action of said retainingmeans, and means for latching said supply valve in its open positionupon movement of said bypass valve to its closed position.

References Cited in the file of this patent UNITED STATES PATENTS

